A surprise birthday getaway has turned into a "nightmare" for a Canberra couple badly injured in a crash in Thailand on Monday.

Shani Bourne and Sam William were riding through Patong on a hired scooter when a car swerved towards them. As they veered to avoid it, they crashed into a parked truck.

Ms Bourne, 25, was rushed to hospital with a fractured pelvis, a broken nose and several facial injuries as well as a brain bleed, while Mr William, 25, suffered a broken arm.

They were due to fly home on Tuesday but, speaking from hospital in Phuket, Ms Bourne said the pair had since been stranded in Thailand as they were unable to afford the $80,000 cost of medical transport home.

"[The doctors] refuse to let us fly with my condition and because our insurance refuses to cover us we have nearly no money left and no way home," she said.

Ms Bourne is now desperate to return to Canberra by Christmas to be reunited with her two young sons, Joey and Anthony.

The trip was her first overseas - a birthday surprise from Sam.

If the couple cannot afford a medi-evac trip, she said they would have to wait until doctors clear her to fly commercially in business class, where she could lie down, but that could take weeks.

Her sister Kiandra Bourne said the pair's insurance claim had been rejected as Mr William's Australian motorcycle licence had lapsed. The Australian embassy had been unable to help them but the family had already sent $15,000, "all we could", she said.

The Department of Foreign Affairs and Trade confirmed on Thursday it was "providing consular assistance to an Australian woman injured in Thailand".

While embassies overseas can help Australians liaison with local hospitals and authorities, consular staff cannot pay for medical costs, provide medical services or medications or query treatment on behalf of Australians overseas.

Ms Bourne said she was still in a lot of pain but her injuries were slowly healing. She still needed another $3000 CT scan to see if the bleeding had stopped in her brain.